• Korean Journal of Pharmacognosy
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• v.50 no.3
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• pp.198-204
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• 2019

A facile and convenient method was developed for the mass production of epigallocatechin gallate (EGCG) rich green tea extract (Er-GTE). The Er-GTE was successfully obtained from the crude water extract of green tea by the combination of two step purification, i.e., a simple adsorption process on the cation exchange resins (Trilite SCR-B) followed by the chromatography with Diaion HP-20 resins. The green tea extract produced by water extraction under $45^{\circ}C$ was subjected to adsorb on the strongly acidic cation exchange resin, Trilite SCR-B. The eluate passed through the resin was reabsorbed on Diaion HP-20 resin, which was subjected to elute with a mixture of water and alcohol by conventional chromatographical manner. The EGCG content in Er-GTE was estimated above 97% by HP-LC analysis and the newly developed method was regarded as the most suitable and appropriate process for the mass production of epigallocatechin gallate rich green tea extract (Er-GTE).

• Preventive Nutrition and Food Science
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• v.7 no.2
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• pp.151-156
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• 2002

Antioxidant activity or green tea extracts (GTE) was evaluated in soybean oil (SBO), rice bran oil (RBO) and winterized rice bran oil (WRBO) stored at 63$^{\circ}C$ for 36 days. Lipid oxidation of the oils was determined using the active oxygen method (AOM), peroxide value (POV), change in unsaturated free fatty acid concentrations and by sensory evaluation. SBO had a higher concentration of the polyunsaturated fatty acids, linoleic and linolenic acid than RBO and WRBO. WRBO and RBO were more stable against lipid oxidation than SBO. Addition of GTE (200 ppm) to the stored oils, increased the induction period (IP) in AOM, reduced the increase in POV, and lessened the change in unsaturated fatty acids. Furthermore, GTE prevented the development of rancid flavors resulting from storage, all of which demonstrate the protective antioxidative activity of GTE. However, oil color became darker in the GTE treated oils. The antioxidant protection of GTE was most effective in RBO.

• Biomedical Science Letters
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• v.28 no.1
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• pp.50-57
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• 2022

In this study, we tried to examine the possibility of developing a dental product such as tooth decay prevention and oral hygiene by manufacturing a natural polymer film for oral use. Natural polymer films were prepared from shark byproduct extract (SBE) and gellan gum (GG). As an antibacterial substance, the antibacterial activity of green tea extract against tooth decay-causing bacteria was measured. An film was prepared by adding green tea extract to the composition of SBE and GG. The mechanical, solubility, moisture content and antibacterial function of the prepared film were investigated in detail. Also, the incorporation of GTE into the SBE/GG film improved the physical performance of the film. Increasing the content of GTE improved the antioxidant and antibacterial properties of the film. Formulation of antimicrobial SBE/GG film containing green tea extract was established and these results evidently showed potential for cavity prevention products application.

• Journal of Embryo Transfer
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• v.30 no.1
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• pp.1-6
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• 2015

The cold shock of spermatozoa is associated with oxidative stress induced by reactive oxygen species. This study was conducted to evaluate the toxicity of natural antioxidant green tea extract (GTE) in lactose-egg yolk (LEY) extender during boar sperm cooling prior to freezing. Spermatozoa were cooled to $5^{\circ}C$ for 3 h in LEY extender containing 0 (control), 1, 10, 100 or 1,000 mg/l of GTE, re-suspended with LEY-glycerol-Equex extender and cooled at $5^{\circ}C$ for 30 min. Sperm progressive motility, viability and phosphatidylserine (PS) translocation were evaluated. PS translocation was assayed by flow cytometry using Annexin V-FITC apoptosis detection kit. The sperm function including progressive motility, viability and PS translocation was not significantly different regardless of GTE concentrations (P>0.05). In conclusion, this study demonstrated non-toxicity of GTE supplement in LEY extender during sperm cooling.

• Journal of the Korean Society of Food Science and Nutrition
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• v.28 no.3
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• pp.599-606
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• 1999

Water extracts of persimmon leaf tea(PLTE), green tea(GTE) and oolong tea(OTE), at the con centration used for human consumption, were examined for inhibitory effects on the mutagenicity of major classes of dietary and environmental mutagens including indirect acting mutagens, B[ ]P (benzo[ ]pyrene), IQ(2 amino 3 methylimidazo[4,5 f]quinoline), 2 AA(2 aminoanthracene) in the presence of S9 mix and direct acting mutagen, 4 NQO(4 nitroquinoline 1 oxide) without S9 mix, using the modified Ames Salmonella/microsome assay. PLTE, GTE and OTE showed very potent and concentration dependent antimutagenic effects against indirect acting mutagens B[ ]P and IQ. At the maximum concentration(16,200 g/plate) of each tea extract, number of colonies decreased in a dose dependent manner up to 82~100%. Similar inhibition of PLTE, GTE and OTE were seen at higher concentration in the mutagenicity of the 2 AA following an initial increase in the activity at lower concentration. However, the mutagenicity of the direct acting mutagen 4 NQO were not suppressed at lower concentration of the three tea extracts, and higher concentration of the tea extracts enhanced mutagenic activity of the mutagen. There were no differences in the mode of antimutagenesis between PLTE, GTE, and OTE, in both Salmonella typhimurium TA98 and TA100 strains against the same mutagen. In conclusion, the water extracts of persimmon leaf tea, green tea and oolong tea possess marked antimutagenic potential against a variety of important dietary and environmental indirect acting mutagens, but the activity was not observed against the direct acting mutagens. These results suggest that the mode of inhibitory action may not have resulted from direct interaction between tea extracts and the mutagens, but rather from indirect metabolic inactivation of mutagens by tea extracts.

• Food Science and Biotechnology
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• v.15 no.3
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• pp.478-481
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• 2006

This study investigated the antimicrobial activity of soy protein isolate (SPI) film containing green tea extract (GTE, 1-4%, w/w) on dental caries-inducing bacterium (Streptococcus mutans), food pathogenic (Staphylococcus aureus, Escherichia coli 0157, Salmonella typhimurium), and spoilage (Pseudomonas aeruginosa) bacteria. The physical and mechanical properties of the SPI film containing GTE were also studied. The SPI film containing GTE (4%, w/w) exhibited good antimicrobial activity against S. mutans and S. aureus. The antimicrobial activity of the SPI film containing GTE increased against S. mutans as the concentration of GTE increased up to 4%(w/w). SPI films containing GTE showed lower tensile strength and elongation, and higher total soluble matter than those of control SPI film. Therefore, GTE can be used as one of antimicrobial agents for anti-dental caries and food packaging films.

• BMB Reports
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• v.38 no.5
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• pp.563-570
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• 2005

Tamoxifen citrate (TAM), is widely used for treatment of breast cancer. It showed a degree of hepatic carcinogenesis. The purpose of this study was to elucidate the antioxidant capacity of green tea (Camellia sinensis) extract (GTE) against TAM-induced liver injury. A model of liver injury in female rats was done by intraperitoneal injection of TAM in a dose of $45\;mg\;Kg^{-1}\;day^{-1}$, i.p. for 7 successive days. GTE in the concentration of 1.5%, was orally administered 4 days prior and 14 days after TAM-intoxication as a sole source of drinking water. The antioxidant flavonoid; epicatechin (a component of green tea) was not detectable in liver and blood of rats in either normal control or TAM-intoxicated group, however, TAM intoxication resulted in a significant decrease of its level in liver homogenate of tamoxifen-intoxicated rats. The model of TAM-intoxication elicited significant declines in the antioxidant enzymes (glutathione-S-transferase,glutathione peroxidase, superoxide dismutase and catalase) and reduced glutathione concomitant with significant elevations transaminase) levels. The oral administration of 1.5% GTE to TAM-intoxicated rats, produced significant increments in the antioxidant enzymes and reduced glutathione concomitant with significant decrements in TBARS and liver transaminases levels. The data obtained from this study speculated that 1.5% GTE has the capacity to scavenge free radical and can protect against oxidative stress induced by TAM intoxication. Supplementation of GTE could be useful in alleviating tamoxifen-induced liver injury in rats.

• The Korean Journal of Food And Nutrition
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• v.13 no.1
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• pp.36-44
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• 2000

Survival of pathogenic bacteris(S. aureus, L. monocytogenes, E. coli and S. typhimurium) in tryptic soy broth containing green tea water extract(GTW), green tea ethanol extract(GTE), potassium sorbate (PS) and sodium benzoate(SB) stored at various pH was evaluated. Tryptic soy broth(TSB) containing 0∼2%(w/v) of green tea extracts and preservatives adjusted to pH 5.5, 6.0, 6.5 and 7.0 was inoculated approximately 105 CFU/ml of pathogenic bacteria and incubated at 35$^{\circ}C$ for 24∼48 hours. Survival of bacteria was determined by viable cell counts of bacterial culture at each pH. Minimum inhibitory concentration(MIC) and minimum bactericidal concentration(MBC) of green tea extracts and preservatives against pathogenic bacteria were derived from survival curves of each bacteria. Antibacterial activities of green tea extracts increased with increasing pH but those of preservatives decreased with increrasing pH. S. aureus was the most sensitive strain to GTW and GTE but the most resistant to PS and SB. The MICs of green tea extracts to S. aureus were 0.52∼0.98% at pH 5.5∼6.0 and non inhibitory at pH 7.0. S. typhimurium was the most resistant to green tea extracts while the most sensitive to SB. The MICs of green tea extracts to S. typhimurium were 0.46∼1.62% at pH 5.5∼6.0 and 2% of PS was bactericidal at pH 5.5. 1.0∼2.0% of GTE were bactericidal to all strains tested except L. m9oncytogenes at pH 7.0. GTE was most efficient at inactivating pathogenic bacteria, generally followed by GTW, PS and SB.

• Advances in Traditional Medicine
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• v.5 no.2
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• pp.137-143
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• 2005

Doxorubicin induces oxidative stress leading to cardiotoxicity causing electrocardiogram abnormalities and increases in biomarkers associated with toxicity. Green tea extract (GTE) is reported to possess antioxidant activity mainly via its polyphenolic constituent, catechins. This study was intended to determine the effect of various doses of GTE (25, 50 and 100 mg/kg/day p.o. for 30 days) on doxorubicin-induced electrocardiographic and biochemical changes in rat heart. The latter included lactate dehydrogenase, creatine kinase, and glutamic oxaloacetate transaminase in serum and superoxide dismutase, catalase, and reduced glutathione, as well as membrane bound enzymes like $Na^+K^+ATPase,\;Ca^{2+}ATPase,\;Mg^{2+}ATPase$ and decreased lipid peroxidation in heart tissue Results demonstrated that rats which received GTE were less susceptible to such changes indicating protection afforded by GTE.

• Preventive Nutrition and Food Science
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• v.7 no.3
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• pp.255-260
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• 2002

Yukwa is a popular Korean traditional fried rice snack. The high fat content and porous structure of Yukwa cause it to rapidly become rancid, presenting difficult challenges for commercial distribution. In this study, an-tioxidant activities of green tea extracts (GTE) were evaluated in Yukwa fried in soybean oil (SBO), rice bran oil (RBO) and winterized rice bran oil (WRBO) during storage at 4$0^{\circ}C$ for 12 weeks. Lipid oxidation of Yukwa was determined by acid value (AV), peroxide value (POV), p-anisidine value(AnV), totox value and sensory evaluation. The addition of GTE to the oils reduced the increases in AV, POV, AnV, and totox. Totox increased most vapidly in Yukwa fried in SBO, fellowed by RBO>WRBO>SBO+200 ppm GTE>RBO+200 ppm GTE > WRBO + 200 ppm GTE (p<0.05). Sensory evaluation revealed that the addition of 200 ppm GTE delays rancidity in Yukwa by 7~8 weeks; providing compelling evidence that GTE is an effective antioxidant for Yukwa.